| 研究課題/領域番号 |
25286008
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| 研究種目 |
基盤研究(B)
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| 研究機関 | 大阪大学 |
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研究代表者 |
VERMA Prabhat 大阪大学, 工学(系)研究科(研究院), 教授 (60362662)
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| 研究分担者 |
齊藤 結花 大阪大学, 工学(系)研究科(研究院), 准教授 (90373307)
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| 研究期間 (年度) |
2013-04-01 – 2016-03-31
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| キーワード | ナノプローブ / ナノマイクロ科学 / ナノ構造物理 / 近接場光学顕微鏡 |
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| 研究概要 |
In this study, it is intended to develop an extremely sensitive near-field Raman microscope based on plasmon hybridization of two metallic nanostructures, namely a nano-tip and a nano-film. This research starts with theoretical optimization of the parameters involved in fabrication. In the first year of this project, we have achieved the following:
1. Optimization of metallic tip-film system:
We have performed 3D-FDTD simulations on the tip-film system. This was done for various parameters of the tip, such as the base material under the metal, the tip cone-angle, the tip-apex diameter etc., for the gap distance, and for the film roughness. As expected, the simulated scattering spectra show strong dependence on the film thickness.
2. Obtaining tunability in plasmon resonance:
In addition to the dependence on the film thickness, the plasmon resonance also shows dependence on the kind of metal. While the resonance for Ag varies from about 400 nm to 650 nm, it varies from about 600 nm to 900 nm for Au, confirming that we can tune the plasmon resonance anywhere in the visible spectrum.
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| 現在までの達成度 (区分) |
現在までの達成度 (区分)
2: おおむね順調に進展している
理由
The starting work in this research is to perform a 3D-FDTD simulation to optimize various parameters of the tip-film system. This is necessary in order to obtain the desired plasmon hybridization and to theoretically confirm the degree of confinement and enhancement as well as the tuning of the plasmon resonance. Once we successfully optimize the parameters by numerical simulation, the next step is to fabricate the same structures and examine them practically, and finally utilize them for highly sensitive optical nanoimaging. In this year, we have been successful in optimize various parameters and have theoretically obtained the tunability in plasmon resonance by calculating the absorption spectra for varying film thickness. This is an important result, utilizing which we can take up the next step in research.
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| 今後の研究の推進方策 |
After optimization through theoretical simulation, we will move towards the fabrication. We will fabricate the plasmonic nano-tip by evaporating silver or gold on commercially available AFM cantilever, which is made of silicon. First, the cantilever will be oxidized under high temperature water-vapor, so that the base material becomes silicon-dioxide. Then the metal will be evaporated on this oxidized cantilever tip in ultra-high vacuum. In order to obtain high quality plasmon hybridization, it is necessary to have a very smooth metallic surface on the tip with surface roughness under 1-2 nm. We will optimize the evaporation parameters, such as the vacuum and the evaporation rate, to obtain the smooth surface. This will also be done for obtaining a very smooth metal film on a glass substrate. Both the tip and the film will be coated with an ultra thin layer of SiO2, so that the gap between the tip and the film can be maintained at a value that was optimized numerically in the first part. After successful fabrication, we will confirm functioning of the tip-film system and finally apply it in TERS measurements to study various samples and obtain nanoimaging, as planned.
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| 次年度の研究費の使用計画 |
本年度（平成２５年度）は、研究プロジェクト１年目で、研究のシュミレーションに時間を費やすことが多く、計算ソフトなどを購入し、実際の実験研究準備であったことと、２年目以降、本格的な実験設備に投資予定があるため繰り越した。
平成２７年度以降、このプロジェクトが大きく進むため、高額な実験装置、備品購入を計画している。
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